Linear ball guided voice coil motor for folded optic

ABSTRACT

Actuators for carrying and actuating a lens having a first optical axis, the lens receiving light folded from a second optical axis substantially perpendicular to the first optical axis, comprising first and second VCM engines coupled to the lens and first and second linear ball-guided rails operative to create movement of the lens in two substantially orthogonal directions upon actuation by respective VCM engines.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a 371 application from international patentapplication PCT/IB2017/054088 and is related to and claims priority fromU.S. Provisional Patent Application No. 62/359,222, filed Jul. 7, 2016,which is incorporated herein by reference in its entirety.

FIELD

Embodiments disclosed herein relate in general to actuating mechanisms(“actuators”) and in particular to voice coil motor (VCM) actuators fordigital cameras.

BACKGROUND

High-end digital camera modules, and specifically cellphone (e.g.smartphone) digital cameras include mechanisms that enable advancedoptical function such as focus or optical image stabilization (OIS).Such mechanisms may actuate (e.g. displace, shift or tilt) an opticalelement (e.g. lens, image sensor, mirror) to create the desired opticalfunction. A commonly used actuator is based on voice coil motor (VCM)technology. In VCM technology, a permanent (or “fixed”) magnet and acoil are used to create actuation force. The coil is positioned in thevicinity of the magnetic field of the fixed magnet. Upon driving currentin the coil, a Lorentz force is created on the coil, an in return anequal counter-force is applied on the magnet. The magnet or the coil isrigidly attached to an optical element to construct an actuatedassembly. The actuated assembly is then moved by the magnetic Lorenzforce. Henceforth, in this description, a VCM will be referred to alsoas “VCM engine” and an actuator including such a VCM (or VCM engine)will be referred to as to as “VCM actuator” or simply “actuator”.

In addition to the magnetic force, a mechanical rail is known to set thecourse of motion for the optical element. The mechanical rail keeps themotion of the lens in a desired path, as required by optical needs. Atypical mechanical rail is known in the art as “spring-guided rail”, inwhich a spring or set of springs is used to set the motion direction. AVCM that includes a spring-guided rail is referred to as a“spring-guided VCM”. For example, US patent application No. 20110235196discloses a lens element shifted in a linear spring rail to createfocus. For example, international patent application PCT/IB2016/052179discloses the incorporation and use of a spring guided VCM in a foldedcamera structure (“FCS”—also referred to simply as “folded camera”). Thedisclosure teaches a lens element shifted to create focus and OIS and anoptical path folding element (OPFE) shifted in a rotational manner tocreate OIS. Also, PCT/IB2016/052179 teaches AF+OIS in a folded actuatorwhere the actuator dos not add to the module height.

Another typical mechanical rail is known in the art a “ball-guidedrail”, see e.g. U.S. Pat. No. 8,810,714. With a ball-guided rail, thelens is bound to move in the desired direction by set of balls confinedin a groove (also referred to as “slit”). A VCM that includes aball-guided rail is referred to as a “ball-guided VCM”. A ball-guidedVCM has several advantages over a spring-guided VCM. These include: (1)lower power consumption, because in a spring-guided VCM the magneticforce has to oppose a spring mechanical force, which does not exist in aball-guided VCM, and (2) higher reliability in drops that may occurduring the life-cycle of a camera that includes the VCM. The actuationmethod in U.S. Pat. No. 8,810,714 is designed for a standard non-foldedlens, where the lens optical axis is directly pointed at the object tobe photographed and cannot be used in a folded camera.

In view of the above, there is a need for, and it would be advantageousto have a linear ball guided VCM inside a folded camera to reduce thefolded camera dimensions, in particular camera height and/or width. Inaddition, there is a need to show such a structure in a combination withvarious actuation mechanisms for the OPFEs in these cameras.

SUMMARY

Aspects of embodiments disclosed herein relate to VCMs to actuatorsincluding such VCMs, the actuators having linear ball-guided rails forAF and OIS in a folded camera, and to digital cameras, and in particularto cameras with folded optics that incorporate such VCMs.

In some exemplary embodiments there is provided an actuator for carryingand actuating a lens holder with a lens, the lens having a first opticalaxis, the lens receiving light folded from an optical path along asecond optical axis that is substantially perpendicular to the firstoptical axis, the actuator comprising a first VCM engine coupled to thelens holder, a second VCM engine coupled to the lens holder, a firstlinear ball-guided rail operative to create a first movement of the lensholder upon actuation by the first VCM engine, wherein the firstmovement is in a first direction parallel to the first optical axis, anda second linear ball-guided rail operative to create a second movementof the lens holder upon actuation by the second VCM engine, wherein thesecond movement is in a second direction that is substantiallyperpendicular to the first optical axis and to the second optical axis.

In an exemplary embodiment, the first movement is for focus and thesecond movement is for OIS.

In an exemplary embodiment, an actuator further comprises a middlemoving frame that includes at least one groove in the first directionand at least one groove in the second direction.

In an exemplary embodiment, the lens holder and the lens are made as onepart.

In an exemplary embodiment, each of the first and second linearball-guided rails includes a pair of grooves having at least one balllocated therebetween.

In an exemplary embodiment, the first and second VCM engines includerespective first and second VCM magnets.

In an exemplary embodiment, an actuator further comprises a static base,wherein the lens holder is movable only along the first direction withrespect to the middle moving frame and wherein the middle moving frameis movable only along the second direction with respect to the staticbase.

In an exemplary embodiment, an actuator further comprises a static base,wherein the lens holder is movable only along the second direction withrespect to the middle moving frame and wherein the middle moving frameis movable only along the first direction with respect to the staticbase.

In an exemplary embodiment, the first and second VCM magnets are fixedlyattached to the lens holder.

In an exemplary embodiment, the first VCM magnet is fixedly attached tothe lens holder and the second VCM magnet is fixedly attached to themoving frame.

In an exemplary embodiment, the first VCM magnet is fixedly attached tothe moving frame, and the second VCM magnet is fixedly attached to thelens holder.

In an exemplary embodiment, the first VCM engine and the second VCMengine include respective first and second VCM coils mechanicallycoupled to the static base.

In an exemplary embodiment, an actuator further comprises at least oneferromagnetic yoke attached to the static base and used to pull thefirst VCM magnet in order to prevent both the first and the secondlinear ball-guided rail from coming apart.

In an exemplary embodiment, an actuator further comprises at least oneferromagnetic yoke attached to the static base and used to pull thefirst VCM magnet or the second VCM magnet in order to prevent both thefirst and the second linear ball-guided rail from coming apart.

In an exemplary embodiment, an actuator further comprises at least oneferromagnetic yoke attached to the static base and used to pull thesecond VCM magnet in order to prevent both the first and the secondlinear ball-guided rail from coming apart.

In an exemplary embodiment, the first and second VCM coils and the firstand second VCM magnets are respectively separated by a constantdistance.

In an exemplary embodiment, an actuator further comprises a firstposition sensor and a second position sensor for measuring a position ofthe lens upon the movement in the first and second directions,respectively.

In an exemplary embodiment, the first and second position sensors areHall bar position sensors operative to measure the magnetic field of thefirst and the second VCM magnets, respectively.

In some exemplary embodiments, any of the actuators above may beincluded in a folded camera together with an OPFE that folds the lightfrom the optical path along the second optical axis to an optical pathalong the first optical axis, wherein the OPFE is tiltable around thesecond direction by a spring based mechanism or a ball based mechanism.

In some exemplary embodiments, the folded camera is included togetherwith an upright camera in a dual-aperture camera.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects, embodiments and features disclosed herein will become apparentfrom the following detailed description when considered in conjunctionwith the accompanying drawings, in which:

FIG. 1A shows an isomeric view of a linear ball guided VCM actuatoraccording to an exemplary embodiment disclosed herein;

FIG. 1B shows the VCM actuator of FIG. 1A in an exploded view;

FIG. 1C shows a top actuated sub-assembly of the VCM actuator from abottom view;

FIG. 1D shows a middle moving frame of the VCM actuator from a top view;

FIG. 1E shows a middle moving frame of the VCM actuator from a bottomview;

FIG. 1F shows a base of the VCM actuator in isometric view;

FIG. 1G shows an EM sub-assembly of the VCM actuator in isometric view;

FIG. 1H shows an isomeric view of a linear ball guided VCM actuatoraccording to another exemplary embodiment;

FIG. 1I shows the VCM actuator of FIG. 1H in an exploded view;

FIG. 1J shows an isomeric view of a linear ball guided VCM actuatoraccording to yet another exemplary embodiment;

FIG. 1K shows the VCM actuator of FIG. 1J in an exploded view;

FIG. 2A shows an embodiment of a folded camera that includes an actuatordisclosed herein;

FIG. 2B shows an embodiment of a folded camera that includes an actuatordisclosed herein and an OPFE rotated by one embodiment of a rotationalspring based mechanism;

FIG. 2C shows an embodiment of a folded camera that includes an actuatordisclosed herein and an OPFE rotated by another embodiment of arotational ball based mechanism;

FIG. 3 shows an embodiment of a dual-camera that includes a foldedcamera as in FIG. 2C together with a non-folded (up right) camera.

DETAILED DESCRIPTION

FIG. 1A shows an isomeric view of a linear ball guided VCM actuator 100according to an exemplary embodiment disclosed herein. FIG. 1B showsactuator 100 in an exploded view. Actuator 100 enables the shift of alens 150 having an optical axis 160 (also referred to as “first opticalaxis”) in two directions in a plane (i.e. the X-Y plane in the shownfigures), as described below: AF operation in a direction 162 and OISoperation in a direction 164. Actuator 100 has exemplarylength/width/height dimensions in the range of 3-40 mm, i.e. actuator100 can be contained in a box with dimension of 3×3×3 mm³ to 40×40×40mm³. The description continues with reference to a coordinate system XYZshown in FIGS. 1A and 1B as well as in a number of other figures.

In actuator 100, lens 150 is positioned and held in a lens holder (orlens carrier) 102 that fits the shape of lens 150. In some embodiments,lens holder 102 and lens 150 may be a single part. In some embodiments,they may be separate parts. In the following description and claims, theterm “lens holder” may be describing a lens holder only, or a unifiedpart (component) that includes a lens holder and a lens. Lens holder 102may be made, for example, by plastic molding, or alternatively by othermethods. Three magnets 104, 106 and 108 are fixedly attached (e.g.glued) to lens holder 102 from below (in the negative Z direction in thefigure). The assembly of lens holder 102 and magnets 104-108 will bereferred to henceforth as “top actuated sub-assembly” 110. FIG. 1C showstop actuated sub-assembly 110 from a bottom view. Lens holder 102includes four grooves, 102 a-d. Grooves 102 a-d are parallel to eachother and are along the Y-axis. Grooves 102 a-d are used to guide topactuated sub-assembly 110 along the Y direction.

Actuator 100 further includes a middle moving frame 112, typically madeof plastic. FIGS. 1D and 1E show middle moving frame 112 from top andbottom views, respectively. Middle moving frame 112 includes eightgrooves 112 a-h, four grooves 112 a-d on a top surface of adaptor 112along the Y direction and four grooves 112 e-h on a bottom surface ofadaptor 112 are along the X direction. Top actuated sub-assembly 110 ispositioned on top of middle moving frame 112 such that grooves 112 a-dare just below and parallel to grooves 102 a-d, respectively.

In the embodiment shown, four balls 114 a-d are positioned on top ofgrooves 112 a-d (one ball on top of each groove) such that balls 114 a-dspace apart lens holder 102 and middle moving frame 112 and prevent thetwo parts from touching each other. In other embodiments, actuator 100may have more than one ball on top each groove 112 a-d, for example upto 7 balls per groove. Balls 112 a-d may be made from Alumina or anotherceramic material, from a metal or from a plastic material. Typical balldiameters may be in the range of 0.3-1 mm. Other ball sizes andpositioning considerations may be as in co-owned international PCTpatent application PCT/IB2017/052383 titled “Rotational Ball GuidedVoice Coil Motor”.

Since lens holder 102 and middle moving frame 112 are exemplarilyplastic molded, there is some tolerance allowed in part dimensions,typically a few tens of microns or less for each dimension. Thistolerance may lead to misalignment of position between adjacent (facing)grooves 102 a-102 b-112 a-112 b and\or 102 c-102 d-112 c-112 d. Tobetter align the grooves, grooves 102 a-d, 112 a-b may be V-shaped, i.e.have a V cross-section shape to ensure ball positioning, while grooves112 c-d may have a wider, rectangular cross-section. Grooves 102 a-b and112 a-b are aligned during assembly, while the alignment of grooves 102c-d and 112 c-d has a small freedom allowed by the rectangular crosssection.

The assembly of top actuated sub-assembly 110, balls 114 a-d, and middlemoving frame 112 will be referred to henceforth as “bottom actuatedsub-assembly” 120.

Actuator 100 further includes a base 122, typically made of plastic(FIG. 1B and FIG. 1F). Base 122 is molded with four grooves 122 a-dalong the X direction. Bottom actuated sub-assembly 120 is positioned onthe top of base 122 such that grooves 122 a-d are parallel to grooves112 e-h respectively. In the embodiment shown, base 122 only serves aspart of actuator 100. In other embodiments, the base plastic molding mayextend to serve for other purposes, such as a base for an actuatorassociated with a prism, to hold a camera sensor, to hold a shield, toprevent stray light and dust from reaching image sensor, etc.

Four balls 124 a-d are positioned on top of grooves 122 a-d (one ball ontop of each groove) such that balls 124 a-d space middle moving frame112 apart from base 122 and prevent the two parts from touching eachother. In other embodiments, actuator 100 may have more than one ball ontop each groove 122 a-d, for example up to 7 balls per groove. The size,material and other considerations related to balls 124 a-d are similarto those of balls 114 a-d.

Actuator 100 further includes three metallic ferromagnetic yokes 130,132 and 134 fixedly attached (e.g. glued) to base 122 from above(positive Z direction in the figure) such each yoke is positioned belowa respective one of magnets 104, 106 and 108. In other embodiments,ferromagnetic yokes 130, 132 and 134 may be fixedly attached to base 122from below. Each yoke pulls its respective magnet by magnetic force inthe negative Z direction, and thus all yokes prevent both top actuatedsub-assembly 110 and bottom actuated sub-assembly 120 from detachingfrom base 122. Balls 114 a-d prevent top actuated sub-assembly 110 fromtouching middle moving frame 112 and balls 124 a-d prevent bottomactuated sub-assembly 120 from touching base 122. Both top actuatedsub-assembly 110 and bottom actuated sub-assembly 120 are thus confinedalong the Z-axis and do not move in positive or negative Z directions.The groove and ball structure further confines top actuated sub-assembly110 to move only along the Y-axis and bottom actuated sub-assembly 120to move only along the X-axis.

Actuator 100 further includes an electro-magnetic (EM) sub-assembly 140,see FIG. 1B and FIG. 1G. EM sub-assembly 140 includes three coils 142,144 and 146, two Hall bar elements 148 and 150 and a PCB 152. Coils142-146 and Hall bar elements 148-150 are soldered (each one separately)to PCB 152. Coils 142-146 have exemplarily each a “stadium” shape andtypically include a few tens of coil windings (i.e. in a non-limitingrange of 50-250), with a typical resistance of 10-30 ohm. PCB 152 allowssending input and output currents to coils 142-146 and to Hall barelements 148-126, the currents carrying both power and electronicsignals needed for operation. PCB 152 may be connected electronically tothe external camera by wires (not shown). EM sub-assembly 140 ispositioned between magnets 104-108 and yokes 130-134, such that eachcoil 142-146 is positioned between a respective one of magnets 104-108and a respective one of yokes 130-134. Upon driving a current in a coil(e.g. coil 142), a Lorentz force is created on the respective magnet(i.e. magnet 104); a current in a clockwise direction will create forcein the positive Y direction, while a current in counter clockwisedirection will create a force in the negative Y direction. Similarly,driving a current in coils 144 or 146 will create a respective Lorentzforce on magnets 106 or 108; a current in a clockwise direction willcreate force in the positive X direction, while a current in a counterclockwise direction will create a force in the negative X direction. Afull magnetic scheme (e.g. fixed magnets 130-134 pole direction) isdescribed in detail for example in co-owned patent applicationPCT/IB2016/052179, and is known in the art.

Hall bar element 148 is positioned inside coil 142 and can sense theintensity and direction of magnetic field of magnet 102. Hall barelement 148 can thus measure the respective position of magnet 104 alongthe Y direction. Hall bar element 150 is positioned inside coil 144 andcan sense the intensity and direction of magnetic field of magnet 106and therefore measure the respective positon of magnet 106 along the Xdirection. Two Hall bar elements can thus sense the motion of topactuated sub-assembly 110 in the X-Y plane and can serve as positionsensors for closed loop control, as known in the art and as describedfor example in detail in co-owned patent application PCT/IB2016/052179.Actuator 100 can thus serve to move lens 150 in the X-Y plane as neededby optical demands. The control circuit (not shown) may be implementedin an integrated circuit (IC). In some cases, the IC may be combinedwith Hall elements 148 and\or 150. In other cases, the IC may be aseparate chip, which can be located outside of the camera (not shown).

It may be noted that all electrical connections needed by actuator 100are to EM sub-assembly 140, which is stationary relative to base 122 andto the external world. As such there is no need to transfer anyelectrical current to any moving part.

Embodiment 100 describes a general two-direction actuator. Otherembodiments may have variations as follows:

In embodiment 100, top actuated sub-assembly 110 moves in the Ydirection relative to middle moving frame 112 and to base 122, whilebottom actuated sub-assembly 120 moves in the X direction relative tobase 122. In other actuator embodiments, such as in an actuator 100″shown in FIGS. 1J and 1K below, top actuated sub-assembly 110 may movein the X direction relative to middle moving frame 112 and to base 122,while bottom actuated sub-assembly 120 may move in the Y directionrelative to base 122.

In embodiment 100, there are two VCMs providing force in the Xdirection. This is done to reduce power consumption. In otherembodiments, an actuator may have only one VCM providing force in the Ydirection.

In embodiment 100, there is one VCM providing force in the Y direction.This is done to reduce space. In other embodiments, an actuator may havemore than one VCM in the X direction (for example two VCM).

In embodiment 100, magnets 106 and 108 are fixedly attached to lenscarrier 102 as part of top actuated sub-assembly 110. Since magnets 106and 108 provide force in the X direction and only need to move in the Xdirection relative to the base, in other embodiments magnets 106 and 108may be fixedly attached to middle moving frame 112.

In some embodiments, actuator 100 may include parts not shown infigures. These may include: mechanical shield, electrical connectivityto the external world, driving IC, interface to connect to other cameraparts, etc.

FIG. 1H shows an isomeric view of a linear ball guided VCM actuator 100′according to another exemplary embodiment disclosed herein. FIG. 1Ishows actuator 100′ in an exploded view. Actuator 100′ is similar toactuator 100 in structure (and therefore similar elements/components arenot numbered and/or described) and function, except for a singledifference: in actuator 100, magnets 106 and 108 are attached to lenscarrier 102, while in actuator 100′, magnets 106 and 108 are attachednot to lens carrier 102 but to middle moving frame 112. Attachingmagnets 106 and 108 to middle moving frame 112 allows full decoupling ofthe lens motion along the Y axis from magnets 106 and 108; namely, anymotion of lens carrier 102 along the Y axis will not influence positionreading by Hall sensor element 150.

FIG. 1J shows an isomeric view of a linear ball guided VCM actuator 100″according to yet another exemplary embodiment disclosed herein. FIG. 1Kshows actuator 100″ in an exploded view. Actuator 100″ is similar toactuator 100 in structure (and therefore similar elements/components arenot numbered and/or described) and function, except for the followingdifferences:

a) In embodiment 100, top actuated sub-assembly 110 moves in the Ydirection relative to middle moving frame 112 and to base 122, whilebottom actuated sub-assembly 120 moves in the X direction relative tobase 122. In embodiment 100″, top actuated sub-assembly 110 may move inthe X direction relative to middle moving frame 112 and to base 122,while bottom actuated sub-assembly 120 may move in the Y directionrelative to base 122.b) In actuator 100 magnet 104 is attached to lens carrier 102. Inactuator 100″, magnet 104 is attached to middle moving frame 112 and notto lens carrier 102. Attaching magnet 104 to middle moving frame 112allows full decoupling of the lens motion along the X axis from magnet104; namely, any motion of lens carrier 102 along the X axis will notinfluence position reading by Hall sensor element 148.c) Actuator 100″ is designed such that the total height along the Z axisis equal to the diameter of lens 150 plus a thickness t, where t may beabout 500 μm. In actuator 100″, the lens is inserted from the top. Theinsertion from the top allows to reduce the height of the actuator.d) Yoke 130 is missing in actuator 100″. Sufficient pull force iscreated by yokes 132 and 134 as described above. Yokes 132 and 134 pullmagnets 106 and 108 respectively, and are holding both top actuatedsub-assembly 110 and bottom actuated sub-assembly 120 from detachingfrom base 122. In other embodiments, a single yoke may be sufficient.

FIG. 2A shows an actuator such as actuator 100, 100′ or 100″ included ina folded camera structure 200. For simplicity, the following descriptionrefers to actuator 100, with the understanding that it applies equallywell to actuators 100′ and 100″. In FCS 200, actuator 100 servesexemplarily to move lens 150. Actuation of actuator 100 is done in FCS200 to create autofocus AF (lens motion along X-axis) and OIS (lensmotion along Y-axis) as described in co-owned PCT/IB2016/052179. FCS 200further includes an OPFE 202 and an image sensor 204. OPFE 202 folds thelight from a second optical axis 206 to first optical axis 160.

FCS 200 may further include other parts that are not displayed in FIG.2A, such as a mechanical shield to protect the camera, stray lightlimiters, dust traps, IR filter(s), electrical circuitry for connectionto external devices, control hardware, memory units (e.g. EEPROM),gyroscopes, etc. FCS 200 may further include an actuation mechanism formoving or tilting OPFE 202 for OIS around an axis 208, axis 208 beingsubstantially perpendicular to both optical axis 160 and optical axis206. Note that in FCS 200, magnet 104 and coil 142 are positionedbetween lens 150 and image sensor 204, a region known in the art as the“back focal length” (BFL) of lens 150.

FIG. 2B shows an embodiment numbered 210 of another FCS that includes anactuator such as actuator 100, 100′ or 100″. In FCS 210, OPFE 202 istiltable by a first embodiment of a rotational spring based mechanismnumbered 212. Exemplarily, the mechanism may be based on a VCM. A fulldescription of a rotational spring based VCM, with explanation of itsmethod of operation, is provided in co-owned patent PCT/IB2016/052179.In FCS 210, actuator 100 and VCM 212 are physically separate; in otherembodiments, they may be connected or share parts, for example, byhaving a single unified plastic base.

FIG. 2C shows an embodiment numbered 220 of yet another FCS thatincludes an actuator such as actuators 100 or 100′ or 100″. In FCS 220,OPFE 202 is tiltable (rotatable) by a second embodiment of a rotationalball based mechanism numbered 222. Exemplarily, the mechanism may bebased on a VCM. A full description of a rotational ball guided VCM 222,with explanation of the method of operation, is provided in PCTIB2017/052383. In FCS 220, actuator 100 and VCM 222 are physicallyseparate; in other embodiments, they may be connected or share parts,for example, by having a single unified plastic base.

FIG. 3 shows an exemplary embodiment numbered 300 of a dual-aperturecamera (dual-camera) that comprises a FCS such as FCS 200, 210 or 220and a non-folded (upright) camera 320. In the exemplary embodimentshown, the FCS is similar to FCS 220, but it should be understood thatthe FCS can be any other FCS disclosed herein. Upright camera 320includes a lens 302 and an image sensor 304. Lens 302 has an opticalaxis 306 that is substantially parallel to second optical axis 206.Upright camera 320 may include other parts (not shown), such as anactuation mechanism for lens 302, a shield, electrical circuitry, etc.The usage and operation of a dual-camera structure is described forexample in co-owned U.S. Pat. No. 9,392,188.

Any of the actuators disclosed above may be included in a folded camera,which folded camera may be included together with an upright(non-folded) camera in a dual-aperture camera with folded lens, forexample as described in co-owned U.S. Pat. No. 9,392,188.

While this disclosure describes a limited number of embodiments, it willbe appreciated that many variations, modifications and otherapplications of such embodiments may be made. In general, the disclosureis to be understood as not limited by the specific embodiments describedherein, but only by the scope of the appended claims.

All references mentioned in this specification are herein incorporatedin their entirety by reference into the specification, to the sameextent as if each individual reference was specifically and individuallyindicated to be incorporated herein by reference. In addition, citationor identification of any reference in this application shall not beconstrued as an admission that such reference is available as prior artto the present application.

What is claimed is:
 1. A folded camera, comprising: a) a lens having afirst optical axis and held in a lens holder, the lens receiving lightfolded from an optical path along a second optical axis that issubstantially perpendicular to the first optical axis; b) an opticalpath folding element (OPFE) that folds the light from the optical pathalong the second optical axis to an optical path along the first opticalaxis; c) an image sensor; and d) an actuator for carrying and actuatingthe lens holder holding the lens, the actuator comprising: a first voicecoil motor (VCM) engine coupled to the lens holder, a second VCM enginecoupled to the lens holder, a first linear ball-guided rail operative tocreate a first movement of the lens holder upon actuation by the firstVCM engine, wherein the first movement is in a first direction parallelto the first optical axis, and a second linear ball-guided railoperative to create a second movement of the lens holder upon actuationby the second VCM engine, wherein the second movement is in a seconddirection that is substantially perpendicular to the first optical axisand to the second optical axis.
 2. The folded camera of claim 1, whereinthe first movement is for focus and wherein the second movement is foroptical image stabilization.
 3. The folded camera of claim 1, whereinthe actuator further comprises a middle moving frame that includes atleast one groove in the first direction and at least one groove in thesecond direction.
 4. The folded camera of claim 1, wherein the lensholder and the lens are made as one part.
 5. The folded camera of claim1, wherein each of the first and second linear ball-guided railsincludes a pair of grooves having at least one ball locatedtherebetween.
 6. The folded camera of claim 1, wherein the first andsecond VCM engines include respective first and second VCM magnets. 7.The folded camera of claim 3, wherein the actuator further comprises astatic base, wherein the lens holder is movable only along the firstdirection with respect to the middle moving frame and wherein the middlemoving frame is movable only along the second direction with respect tothe static base.
 8. The folded camera of claim 3, wherein the actuatorfurther comprises a static base, wherein the lens holder is movable onlyalong the second direction with respect to the middle moving frame andwherein the middle moving frame is movable only along the firstdirection with respect to the static base.
 9. The folded camera of claim6, wherein the first and second VCM magnets are fixedly attached to thelens holder.
 10. The folded camera of claim 6, wherein the first VCMmagnet is fixedly attached to the lens holder and wherein the second VCMmagnet is fixedly attached to the moving frame.
 11. The folded camera ofclaim 6, wherein the first VCM magnet is fixedly attached to the movingframe, and wherein the second VCM magnet is fixedly attached to the lensholder.
 12. The folded camera of claim 6, wherein the first VCM engineand the second VCM engine include respective first and second VCM coilsmechanically coupled to the static base.
 13. The folded camera of claim6, wherein the actuator further comprises at least one ferromagneticyoke attached to the static base and used to pull the first VCM magnetin order to prevent both the first and the second linear ball-guidedrail from coming apart.
 14. The folded camera of claim 6, wherein theactuator further comprises at least one ferromagnetic yoke attached tothe static base and used to pull the second VCM magnet in order toprevent both the first and the second linear ball-guided rail fromcoming apart.
 15. The folded camera of claim 12, wherein the first andsecond VCM coils and the first and second VCM magnets are respectivelyseparated by a constant distance.
 16. The folded camera of claim 6,wherein the actuator further comprises a first position sensor and asecond position sensor for measuring a position of the lens upon themovement in the first and second directions, respectively.
 17. Thefolded camera of claim 16, wherein the first and second position sensorsare Hall bar position sensors operative to measure the magnetic field ofthe first and the second VCM magnets, respectively.
 18. The foldedcamera of claim 1, wherein the OPFE is tiltable around the seconddirection by a rotational spring based mechanism.
 19. The folded cameraof claim 1, wherein the OPFE is tiltable around the second direction bya rotational ball based mechanism.
 20. The folded camera of claim 1,included together with an upright camera in a dual-aperture camera.